Hi there: I'm a quite experienced builder/pilot.
I had a serious problem with my first and brand new TRex 500 ESP. Just after only about 6 min of flight (first test/tuning flight) the torque tube front drive gear (part H50096) suddenly stripped and fortunately I saved my bird since is was very low.
Does anyone has had the same problem? What can be the reason of this failure?
Many thanks in advance for any contribute/opinion!

Possibly bad parts. I haven't heard anything like that.

Duc SDo It! Do It!™ AMA:REVOMIXRCK:24005615-01

It happend once on my bird but looks like it is happing... I've talk to guy from LHS and suggested to check TT bearing install that make sure it is not way off from center line (still need to be offset IAW manual)and use auto rotation when you landing...
Tail blade strike is biggest one that causes for the TT gear stripped.